Process of hardening steel.



W. E. NIOKBRSON.

PROCESS OF HARDENING STEEL.

APPLICATION FILED AUG. 12,1907.

Patented Feb. 23, 1915.

2 SHEETSSHEET l.

W. E. NIGKERSON. PROCESS OF HARDENING STEEL. APPLICATION FILED AUG. 12, 1907.

1 9 1 1 9, 1L 1 3 Patented Feb. 23, 1915.

' Z SHEETS-SHEET Z.

5 vwc wfoz jvitncaacaz WILLIAM E. uicxnnson, or camnmnss, acnusn'r'rs;

rnocnss or 1: i

JENING- STEEL.

Application filed August 12, 1e07, Serial n0, saaova.

To all whom it may concern Be it'known that I, WILLLAM E. NIoKnR- sox'. of the city of Cambridge, county of Middlesex, and Commonwealth of Massachusetts, have invented certain new and useful Improvements in Processes of Harden-t ing Steel for Use in the Manufacture of Cutting Implements or Tools, of which the following is a full, clear, and exact specifif cation.

. My invention relates to certain new and useful improvements in methods or processes of treating steel, and more especially to the hardening of steel blanks for use in the manufacture of cuttingimplements or tools.

As is well known, in order to produce a sharp and durable cutting edge, it is necessary that the material be suitably hardened,

and while the hardness of steel willdepend,"

to some extent, upon the constitution or proportions of the ingredients thereof, the hardness of any given piece may be varied within very Wide limits by treatment, and especially by heat treatment.

The usual method of hardening steel con- .for instance, blanks live or six one-thousandths of an inch thick,-such as are em ployed' in the manufacture of the razor blades described in United States Letters quality and uniformity of product, it is- Patent, Number 775,134 issued Gillette November15, tion, while adapted for use in the manufacture of many different articles, is particularly useful in hardening such thin steel to King C.

sheets or blanks, or in cases where the damage to the surface by oxidation or burning 7 caused by the usual methods of hardening ii a metallic bodywhich has been raised by would be objectionable.

I have found that to obtain the highest necessary that the heatingoperation be'so performed that the temperature of the' whole mass under manipulation be"- 'i"aised uniformly to the desired temperature, and

that the chilling thereof be as nearly in stantaneous throughout the entire blank as possible. It is also desirable that the heat be applied quickly as well as imifornhly, as

1904; and my inven ration of the materialy} Furthermore, steel a highly heated condition unites very freely with 'the oxygen: of the air and thus more or less surface ticle. I

I The burningpf the surface or forming ofscale by oxidation occurs more or less in all of the processesof hardening heretofore in use,'but 1n- View of the size ormass of the,

articles, the inconsiderableamountthereof; has been insufficient thin sheet plates or blanks, however, of the character referred to above-and which are required to be of the highest-degree of ex} cellence and uniformity,'the defects above referredto are a serious detriment, and my present invention is intended to overcome them, or to reduce them to a minimum. Other difficulties are also metwitll' in the heating and chilling of thin-blanks, 1 such as the liability to buckle or become-distorted if the heating andchilling v-areyne't pepoxidation t'akes place," often to the detrimentof the finishedarto impair seriously the quahty of the finished product; In treating Specification of was rare t. Patented Feb. 23; i9t5 a gradual heating is apt to, cause'a deterio-' formedrlwithnsuficient uniformity throng out the entire mass, my invention to obviate or reduce to a mimmumall these disadvantages, duce a;finishedlarticle of the'highest degree of excellence, with the .neces'saryihardness and uniformit have found very satisfactory is as follows:

I take thinsteel blanks of the desired size' and shape, and if the desired article is the razor blade hereinbefore referred to, I take thin sheet steel blanks cut from rolled sheets or ribbons, and preferably subject them to a preliminary heating operation by which theirtemperature Will be quickly'raised, so

that when the finalheatingtakes place the danger of buckling or distortion will be reduced to a minimum. This preliminary heating is preferably accomplished by subjecting the blanks to heat radiated from [until it is uniformly raised to about the temand to pro-f and itfis the object of L and the method which E i perature mentioned. Thus the danger of producing" strains or of burning out the surface carbon will be vreduced to a 'mini-' mum nd the blank i i wi prelim? nary temperature without'injurious efi gt The blanks so treated are then preferably subjected to a further heating which raises the temperature to the desired" degree, this depending lar ely upon the object or use to which the finished article is to beput, and in order to produce a uniform product it is very important that this final heating be accurately timed and regulated. This I may be successfully accomplished by subjecting the blanks to a blast flame of constant temperature for a definite period of time; or, as I prefer to do, by placing them between a pair of metallic heatmg members which are maintained at a constant temperatureby means of blow pipes or other suitable apparatus. The heating of the blanks between the hot surfaces not only prevents, to a very large extent, the burning of the surface, but it prevents strain and the distortion of the blanks and keeps them in desired shape and condition. in additionto'this, if the heating bodies be of con.- siderable size or mass, the temperature of the blanks can be successfully determined and maintained with great accuracy and u'niior'mity, wliile at the same time the heated h lanks are protected against oxidation,-

suc as would occur were they maintained freely accessible to the open air. 1

After theblanks have been raised .to the desired temperature, theymust be rapidly cooled, and this operation is generally known as quenching; The greater the rapidity of this quenching operation, the u more perfect will be thejfinished article, and

I have found that a very successful method is to place the heated'blanks between cold surfaces, such as metallic bodies of relatively large mass, which may be kept cool by means of a water circulation or other device, and this will be found to produce a most efficient article.- I also find it desirable, in

some cases, to employ considerable pressure in the quenching operation, as bythis means any distortions or strains are removed, and

I the finished article is uniformly cooled and retained in the desired shape. I have also to the action of a hammer blow for the purpose of insuring their being in the desired condition when the final chilling takes place,

I and in practice I have found it most desirfound it desirable to subject the hot blanks pe'iature thereof by reason of contact with the blank will be extremely small. When properly proportioned, blanks can be properly hardened with great rapidity and can thus be produced in large quantities of a very uniform character. The employment of the preliminary heating operation will be found valuable in carrying out my process, for the reason that it permits of the delivery to the heating blocks of the blanks at such -a temperature as to render them less liable to produce any change in the condition of said-blocks.

In the accompanying drawing forming part of this application, I have shown types .of apparatus which will be found useful in carrying out the foregoing method.

Inthese drawings, Figure 1 illustrates a device designed to be used in performing the first heating operation. Fig. 2, an apparatus designed to perform the second or final heating operation. Fig. 3 shows one of the parts illustrated in Fig. 2. Fig. 4 dis-' closes an apparatus for chilling or chilling the blank when heated, and Fig. 5 is a horizontal section through one of the chilling members in Fig 4.

Referring to ig. 1, the reference numeral 1 indicates the blank held by the carrier 2. Any suitable means may be employed for holding the blank on the carrier but I prefer to use suction means such as are well known in the art and which need not be here described. The heating block or conductor 3 is maintained at the desired temperature by means, of blow pipes 4, 4, 4, suitably arranged and regulated, and the blank to be heated is brought within the heat zone above the heating block 3, and is held there for a suificient time to raise it to the desired temperature. The use of the radiated heat from a heated metallic body is extremely effective for the reason that the blank is not subjected to the direct action of the burning ases of the flames which would tend-to in- ]ure it, and at the same time the temperature can be more easily regulated than when a direct flame is employed.

In Fig. 2, two heatin blocks or conductors 5, 6, are shown, %etween which the blank, which has received the preliminary heating, is placed. These blocks are subjected to the constant action of blowpipes or blasts 4, 4, 4, 4, 4, 4, and, being of considerable size, are thus maintained at a uniform temperature. When a blank is placed 11 on the lower block, the up er one is t en pressed down thereon an the heat of the blocks is thus transmitted to the blank by conduction and also by reason of the blanks being completel buried in the heat zone. It may be desirab e to groove or corru ate the contacting surfaces of the blocks as s own at 7 in Fig. 3, for by so doing, any sticking of the blank to the block will be prevented. A

L J 13 new:

blank treated as thus described will be gradually raised to the desired temperature without strain or distortion and is then ready for the chilling operation which I prefer to carry out by means of the apparatus shown in Figs. 4 and 5. This consists of a pair of chilling blocks 8, 9, which may be hinged together as shown. These blocks have recesses 10 therein with inlet and outlet pipes 11, 12, through which a constant stream of Water is caused to pass for the purpose of maintaining the blocks at a comparatively low'temperature. The blocks are caused to approach one another with a rapid motion or blow and are adapted to be held together firmly after the blow by means of the pivoted arm 13 carrying the roller 14 which bears upon the upper surface of block 9, the lever being operated by a weight 15 connected by a cord 16 thereto. In using this apparatus the blank after having received its final heating in the apparatus disclosed in Fig. 2, is immediately transferred to the lower block 9 as shown. The upper block then drops, striking the blank which is then clamped firmly between the two.

The chilling is thus produced by conduction from the cold blocks, and takes place evenly throughout the entire blank, which at the same time, is held flat and any distortion or strain prevented.

It is important in both heating and chilling operations that the heating or chilling blocks be comparatively large in size or mass with respect to the blank operated upon. By this means the temperature of the blocks will be practically unaffected by contact with the blank and will remain comparatively uniform when treating a large omitted or not, without departing from the.

spirit of the invention, and I do not wish to be understood as limiting myself to a rocess which includes all of the steps hereto ore described, but what ll claim and desire to secure by Letters Patent is:

1. The method of hardening thin steel blanks,:consisting in raising them to a predeterminedhigh temperature by conduction from heated bodies maintained at the desired temperature, and then chilling them.

2. The method of hardening thin steel blanks, consisting in raising them to the necessary high temperature by conduction from previously-heated solid bodies maintained at a substantially uniform temperature, and then chilling them by conduction from solid bodies of sufficient mass as to be substantially unaffected in temperature by contact with the blanks .being treated.

3. The method of hardening thin" steel blanks, consisting in raising them to a moderately-high temperature, subsequently raising them to a higher-temperature by means of conduction from a previously-heated solid body, and then chilling them.

4.. The method of hardening thin steel blanks, consisting in raising them to a moderately high temperature, subsequently raising' them to a higher temperatureby conduction from a previously-heated solid conductor, and then chilling them.

The method of hardening thin steelblanks, consisting in raising them to a moderately high temperature, subsequently confining them andraising them to a higher temperature when so confined, and chilling them.

6. The method of hardening thin steel blanks, consisting in raising them to a mod erately high temperature, subsequently confining them and raising them to a higher temperature when so confined. and chilling them while confined under pressure.

7. The method of hardening razor blades consisting in raising thin steel blanks to a moderately high temperature, subsequently confining them between suitable hot surfaces and raising them to a high temperature, subjecting them to the action of a blow and of a chilling. I

S. The method of hardening razor blades consisting in raising thin steel blanks to a moderately high temperature, subsequently confining them between suitable hot surfaces and raising them to a higher temperature and chilling.

, 9. The method of hardening razor. blades consisting in raising thin steel blanks to a moderately high temperature, subsequentlyconfining them between suitable hot surfaces and raising them to a higher temnot blanks consisting in heating them by conduction from another previously heated solid body maintained ata substantially uniform temperature, andchilling them.

11. The method of hardening thin steel blanks, consisting in heating and chilling them by conduction from solid metallic bodies each of which is maintained at a substantially uniform temperature necessary to effect the heating and chilling operations.

12. The method of hardening thin steel blanks, consisting in-heating them by conduction from previously heated solid bodies maintained at a substantially-uniform temperature. and then chilling them by (3011-. tact with metal bodies maintained at the necessary low temperature. a

13. The method of hardening thin steel blanks, consisting in raising them to the necessary high temperature by conduction from I and fconfining them a by v previouslyheated-solid bodies maintained ata substantially-uniform high temperature, and then chillii gthem by confinement by and contact 'w ithasolid bodiesimainta-il ed at the necessaryllow temperature. 7

I 14.;The method of hardening razor blades consistingin raising thin steel blanks to a moderately high temperature, subsequently confining them between suitable hot surfaces and'raising them to a high temperature, subjecting them to the action of a blow and then chilling.

15. The method of uniformly hardening a series of thin steel blanks consisting in raising them to the necessary high temperature by conduction from a heated body maintained at the desired temperature, and chilling them by contact with a cold body maintained at a substantially uniform temperature.

16. The method of hardening a series of thin steel blanks uniformly, consisting in raising them to the necessary high temperature by inclosin them between heated bodies maintaine at a substantially uniform high temperature, and chilling them between cool bodies maintained at a substantially constant low temperature.

' 17. The method of hardening ajseries of thin steel blanks uniformly, consisting in raising them to the necessary high temperature .by inclosing them between heated bodies maintained at, a substantially uniform high temperature, and chilling them by delivering them upon'a cold metal block and strikingthem with another cold block,

both blocks being maintained at a substan- 7 set my hand in the presence of two subscribing witnesses.

WILLIAM E. NICKERSON.

Witnesses v E. D. CHADWICK, OLIVER MITCHELL. 

